import 'package:flutter/material.dart';

class MyStateWidget extends StatefulWidget {
  @override
  _MyStateWidgetState createState() => _MyStateWidgetState();
}

class _MyStateWidgetState extends State<MyStateWidget>
    with SingleTickerProviderStateMixin {
  TabController _tabController;

  @override
  void initState() {
    super.initState();
    _tabController = TabController(vsync: this, length: choices.length);
  }

  @override
  void dispose() {
    _tabController.dispose();
    super.dispose();
  }

  void _nextPage(int delta) {
    final int newIndex = _tabController.index + delta;
    if (newIndex < 0 || newIndex >= _tabController.length) return;
    _tabController.animateTo(newIndex);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text(" AppBar Bottom Widget"),
          leading: IconButton(
            icon: const Icon(Icons.arrow_back),
            tooltip: '上一页',
            onPressed: (){_nextPage(-1);},
          ),
          actions: <Widget>[
            IconButton(
              icon: const Icon(Icons.arrow_forward),
              tooltip:'下一页' ,
              onPressed:(){_nextPage(1);},)
          ],
          bottom: PreferredSize(
            preferredSize: const Size.fromHeight(48.0),
            child: Theme(
              data: Theme.of(context).copyWith(accentColor: Colors.white12),
              child: Container(
                height: 48.0,
                alignment: Alignment.center,
                child: TabPageSelector(
                  controller: _tabController,
                ),
              ),
            ),
          ),
        ),
        body: TabBarView(
          controller: _tabController,
          children: choices.map((Choice choice){
            return Padding(
              padding: const EdgeInsets.all(16.0),
              child: ChoiceCard(choice:choice),);
          }).toList(),
        ),
      ),
    );
  }
}


class Choice {
  const Choice({this.title,this.icon});
  final String title;
  final IconData icon;
}

const List<Choice> choices = const <Choice>[
  const Choice(title: "Car",icon: Icons.directions_car),
  const Choice(title: 'BICYCLE', icon: Icons.directions_bike),
  const Choice(title: 'BOAT', icon: Icons.directions_boat),
  const Choice(title: 'BUS', icon: Icons.directions_bus),
  const Choice(title: 'TRAIN', icon: Icons.directions_railway),
  const Choice(title: 'WALK', icon: Icons.directions_walk)
];

class ChoiceCard extends StatelessWidget {
  const ChoiceCard({Key key,this.choice}):super(key:key);
  final Choice choice;

  @override
  Widget build(BuildContext context) {
     final TextStyle textStyle = Theme.of(context).textTheme.display1;
     return Card(
       color: Colors.white,
       child: Center(
         child: Column(
           mainAxisSize: MainAxisSize.min,
           crossAxisAlignment: CrossAxisAlignment.center,
           children: <Widget>[
             Icon(choice.icon,size: 128.0,color: textStyle.color),
             Text(choice.title,style: textStyle,)
           ],),),
     );
  }
}